This proposal has two general purposes (a) to determine prospectively the relationship among anthropometric variables, pubertal development, nutritional intake and somatomedin-C and (b) to develop an intervention to prevent adoption of unhealthful weight regulation strategies by adolescents. Seven middle schools will be included in the study. Half of the females (650) in the seventh grade student body population in each of six schools will receive a special 18 session healthy weight regulation curriculum in lieu of regular physical education activities. The remaining half (650) in each of these six schools will receive regular physical education instruction. The seventh school will serve as an additional untreated control for potential diffusion effects. Physiologic measures will include height, body weight, skinfold thickness and Tanner Self-Staging. Biologic measures will include serum cholesterol and somatomedin-C. Self-reported behaviors will include demographics, family weight history, knowledge about human growth and development, assessment of weight-regulation behaviors, assessment of activity in KCal expenditure/week, and food frequency for the past month. Average daily calories, saturated fat, cholesterol, protein, and carbohydrate intake will be calculated from the food frequency. Psychological measurements will include the Eating Disorder Inventory (designed to assess a number of psychological and behavioral characteristics of anorexia and bulimia), the depression and anxiety scales of the SCL-90 and the Moos Family Environment Scale. The nutritional guidelines are derived from the Food and Nutrition Board, National Academy of Sciences and the Task Force of the Nutritional Committee and the Cardiovascular Disease in the Youth Council of the American Heart Association. The curriculum will focus on teaching normal growth and development, energy balance, learning to identify and resist sociocultural influences on excessive weight loss and thinness and how to develop regular exercise habits and healthy nutrition practices.